Wood vs. Trex?

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Forum topic by jasoncarpentry posted 1160 days ago 1678 views 0 times favorited 10 replies Add to Favorites Watch
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111 posts in 1289 days

1160 days ago

I’m starting to build an overhead lumber-storage rack in my shop. I have some Trex (2×4 and 1×6) left over from another project, and I’d like to use it for some or all of this rack. However, I’m concerned about the structural properties of the Trex vs. those of regular 2×4’s, etc. Since Trex is a composite of wood & plastic, does it have as much resistance to bending as wood? Also, its higher density will make the rack itself heavier and possibly more likely to collapse. If that happens while I’m standing under it, well …

I realize that the main advantage of Trex is its resistance to rain & UV light, hence its superiority over wood for outdoor structures like decks. But for this indoor project, is there any good reason to use it instead of wood?

-- Jim in Tennessee

10 replies so far

View Lee Barker's profile

Lee Barker

2163 posts in 1485 days

#1 posted 1160 days ago

Wood is the right choice here, Jim. Good for you for a thought outside the box…there must be other homes for your Trex if you keep thinking you’ll land on it.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View crank49's profile


3380 posts in 1605 days

#2 posted 1159 days ago

If you have any applications for wood in contact with concrete, like in a basement, this is a good material for that. I use it for the sill at the base of a framed wall sitting on concrete, and for base plates on the bottom of table and workbench legs that will be in contact with the concrete floor.

-- Michael :-{| “If you tell a big enough lie and tell it frequently enough, it will be believed.” ― A H

View Dennis Fletcher's profile

Dennis Fletcher

455 posts in 1689 days

#3 posted 1159 days ago

The trex is definitely not meant as a structural material for the application you are talking about. I actually disagree that it could be used for structural anything, as it is prone to bending at much less spans that wood and most would use it like it was a 2×4, unfortunately.

--, Making design and application one. †

View Cosmicsniper's profile


2199 posts in 1793 days

#4 posted 1159 days ago

I build small observatories with Trex decking. If there aren’t closely enough spaced floor joists, you could probably use the deck as a trampoline…it’s THAT flexible.

Definitely use wood…regular 2×4s are cheap and will give you all the support you need for that.

-- jay,

View Spotcheck's profile


8 posts in 1161 days

#5 posted 1157 days ago

As noted – way too flexible. Also – if the weight of the shelves themselves might be the cause of failure on a lumber storage rack, you may want to rethink a couple of the design fundamentals :)

View MrWoodworker's profile


65 posts in 1229 days

#6 posted 1155 days ago

Heavy, bouncy, and not a great choice.


View eaglewrangler's profile


59 posts in 1171 days

#7 posted 1155 days ago

take an old trex board and bend it until it breaks, you will never think of it as structural again. The only hard part of breaking it is knowing to cost of it. It is also unstable, expannding in heat, sagging if spanned more than 16 inches, decking is all it can do.

View devann's profile


1735 posts in 1327 days

#8 posted 1155 days ago

Better go with the wood. Trex has always had to much of a sag factor for me even when used at manufactures recommended spacing specifications. I built myself an overhead lumber storage rack from some 12’ post oak pallet material I came across, it worked fine. After finishing the rack take some measurements from floor to shelving and periodically check them to be sure that everything is staying were you put it. Due to space limitations I had to make mine a cantilever design. Some Simpson connectors can also be used the beef up some of critical joints.

-- Darrell, making more sawdust than I know what to do with

View TheDane's profile


3742 posts in 2297 days

#9 posted 1155 days ago

Trex is a good material for jigs & fixtures in the shop.


-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View ChrisMc45's profile


94 posts in 1494 days

#10 posted 931 days ago

Agree with TheDane & EagleWrangler, all good points. Great decking, also grand for jigs and tool handles as it machines super-smooth. Heavy, flexy; strongest in compression not in tension or torsion.

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